This invention relates to means for deactivating toxic chemical agents. The present invention in particular relates to polymeric or resin deactivation substances or compositions which may be used for the deactivation of toxic chemical agents.
Toxic chemical agents are chemical substances in gaseous, liquid, or solid form, which may, for example, induce choking, blood poisoning, nerve poisoning, etc., in humans and other animals. Chemical warfare agents are examples of toxic chemical agents which may be treated in accordance with the present invention. The present invention will be described hereinafter, in particular, by way of example only, in relation to chemical warfare agents but is applicable to other toxic chemical agents such as pesticides for example.
Over the years, various highly toxic chemical warfare agents have been stockpiled by several nations. The chemical warfare agents include among other substances a variety of organophosphorus and organosulfur compounds. One commonly known chemical warfare agent is Bis-(2-chloroethyl) sulfide, also known as HD). The chemical warfare agents commonly known as G-agents are examples of highly toxic nerve agents; they include TABUN (GA), SARIN (GB), and SOMAN (GD); GD is pinacolyl methylphosphonofluoridate. The G-agents are broadly organic esters of substituted phosphoric acid.
The phosphonothiolates are in particular highly toxic chemical warfare nerve agents currently stockpiled by various governments. The most commonly known of these nerve agents is O-ethyl S-(2-diisopropylamino)ethyl methylphosphonothiolate which is known as VX. VX and its congeners having the phosphonothiolate structure of formula (I)
R1xe2x80x94Sxe2x80x94P(xe2x95x90O)(R2)(OR3)xe2x80x83xe2x80x83(I) 
wherein each of R1 R2 and R3 is selected from the group consisting of hydrogen and an appropriate organic radical or organic functional group; R1 may for example be selected from the group comprising (dialkylamino)alkyl wherein each alkyl group is independently selected from the group comprising straight and branched lower alkyl of 1 to 6 carbon atoms ; R2 may for example be selected from the group comprising straight and branched lower alkyl of 1 to 6 carbon atoms; and R3 may for example be selected from the group comprising straight and branched lower alkyl of 1 to 6 carbon atoms. An alkyl group may for example be methyl, ethyl, isopropyl or the like.
Examples of known techniques for the deactivation of toxic chemical agents may be found in the following U.S. patents the entire contents of each of which is incorporated herein by reference: namely, U.S. Pat. Nos., 4,784,699, 4,874,532, 4,883,608, 5,069,797, 5,126,309, 5,143,621, 5,689,038, 5,710,358 and 5,859,064.
Methods used over the yeas to deactivate toxic chemical agents such as for example the above mentioned such chemical warfare agents have each had problems associated with them such as hazardous reaction products.
The reaction (e.g. hydrolysis) products of VX may, for example, include EA2192, which is nearly as toxic as G series agents; EA2192 is a phosphonothioic acid which has the same basic structure as VX except that R3 is a hydrogen atom (see Formula (I) above). Thus, hydrolysis-based decontamination schemes are not effective against VX.
In view of the biological hazards associated with chemical warfare agents, there is thus a continuing interest in the development of decontamination or deactivation means for the disposal of unwanted stockpiles of chemical warfare agents such as, for example, the stockpiles of the nerve agent VX. There is in particular a continuing need for an effective neutralisation method for the deactivation of toxic chemical agents.
It would be advantageous to have a process for deactivating toxic chemical agents such as, for example, nerve agents at a rapid rate, the nerve agents being in a solid or fluid phase (e.g. in a gaseous or liquid phase), the deactivating agent being a non-aqueous solid phase deactivating agent.
It would in particular be advantageous to have a deactivation means which does not depend on the use of water in order to function, which is capable of use at low temperatures (e.g room temperatures); etc..
It would further be advantageous to have a process for rapidly and safely decontaminating large (e.g. military, commercial, etc..) quantities of such chemical agents.
The present invention relates generally to a resin composition or substance for the deactivation of toxic chemical agents; it in particular relates to halide or halogenated resins (e.g. halide impregnated resins) for the deactivation of toxic chemical agents (e.g. in solid, gas and/or liquid form).
Iodine/resin substances have been proposed for use as a demand disinfectant against biological agents, namely against microorganisms such as fungi, bacteria, viruses etc. As used herein, xe2x80x9cbiological agentxe2x80x9d refers to hazardous biological organism including fungi, viruses and bacteria, (whether in the form of spores or otherwise), as well as eukaryotic parasites such as Giardia.
U.S. Pat. Nos. 3,817,860, 3,923,665, 4,238,477, 4,420,590, 5,431,908, and 5,639,452 describe such iodine/resin substances for devitalising microorganisms; the entire contents of each of these patents is incorporated herein by reference. U.S. Pat. No. 5,639,452, in particular discloses a (demand) disinfectant substance comprising an iodine impregnated ion exchange resin in which the iodine is more tenaciously associated with the resin than with previously known (demand) iodine impregnated resin disinfectants.
It has been determined that halogen/resin substances may be used for the deactivation of toxic chemical agents, i.e. agents other than biological agents.
Thus the present invention in a general aspect provides a method for deactivating a toxic chemical agent comprising contacting said toxic chemical agent with an halogenated resin. The expressions halogenated resin, halide-resin and the like are to be understood herein as including or relating to resin wherein halogen is absorbed or impregnated therein.
The terms xe2x80x9cdeactivatexe2x80x9d, xe2x80x9cdeactivationxe2x80x9d and the like are to be understood as meaning to render any such toxic chemical agent inactive, ineffective, or substantially less effective for causing harm to life or health, and particularly human life or health. Thus such (deactivation) contact is of course to be for a sufficient time and under conditions which are sufficient to produce a reaction product having less toxicity than said toxic chemical agent (e.g. contact with a deactivating amount of a halogenated resin).
The present invention in an additional aspect provides a method for reducing or eliminating unwanted or undesired stockpiles of a toxic chemical agent susceptible to deactivation (e.g oxidation) by halogen substance, which comprises deactivating a toxic chemical agent by contacting said toxic chemical agent (e.g. in a confining means) with an halogenated resin (i.e. with a deactivating amount of a halogenated resin). Such contact is of course to be for a sufficient time and under conditions which are sufficient to produce a reaction product having less toxicity than said toxic chemical agent. The confining means may be a sealed container, a chromatographic like column packed with halogenated resin, etc..
The present invention in another aspect provides a system for deactivating a toxic chemical agent susceptible to oxidation by halogen substance, said toxic chemical agent being in a fluid phase, said system comprising
means for providing a fluid path for the movement of fluid therethrough, and
a halogenated resin disposed in said fluid path such that toxic chemical agent in said fluid phase passing through said fluid path is able to be brought into contact with said resin and be deactivated thereby.
The present invention in a further aspect provides a method for deactivating a toxic chemical agent, said toxic chemical agent being in a fluid phase (i.e. in a liquid, vapour or gas), said method comprising passing said toxic chemical agent in said fluid phase through fluid path means air over an halogenated resin such that said toxic chemical agents contacts said resin and is deactivated thereby.
The present invention in a further additional aspect provides a method for deactivating a toxic chemical agent, wherein when said toxic chemical agent is in a liquid or vapour phase, said method comprises passing said toxic chemical agent over an halogenated resin such that said toxic chemical agents contacts said resin and is deactivated thereby. Vapour phase chemical agent(s) may, for example, be solubilized in an appropriate solvent through any (known) means and the resultant solution may be passed over the halide-resin. However, it is to be noted that halogen fixing solvents and solvents reactive with the halogen/resin are to be avoided.
As used herein, xe2x80x9ctoxic chemical agentxe2x80x9d means a hazardous chemical agent, including but not limited to chemical warfare agents such as the compounds known as GD, HD, and VX, and hazardous industrial chemical agents. The expression xe2x80x9ctoxic chemical agentxe2x80x9d in particular includes any toxic chemical agents which may be susceptible to deactivation (e.g. oxidation) by a halogen substance, i.e. a halogen substance such as described herein. It is believed that the halide substances such as the halogenated resins described herein including those in the above mentioned U.S. patents herein will be effective to deactivate toxic chemical agents which are susceptible to deactivation (e.g. oxidation) by the halogenated substances.
A halogen resin is of course to be chosen on the basis it may be capable of reducing the activities of toxic chemical agents, i.e. on the basis that it is a deactivation halogen resin. The deactivating resin may be a demand-type deactivator, i.e., a substance from which halide ions are released almost entirely on a demand-action basis upon contact with a target agent but that does not otherwise release substantial amounts of the devitalizing and deactivating substance into the environment. Such a demand-type substance essentially would be capable of deactivating target agents on demand, at least until the halide-resin has been exhausted. Such resins as well as a process(es) for their preparation are for example described in U.S. Pat. No. 5,639,452, (Messier); the entire contents of this patent are incorporated herein by reference. Thus, for example, the halide-resin may comprise a demand iodinated anion exchange resin or, more particularly, the halide-resin may comprise a demand iodinated strong base anion exchange resin.
In accordance with the present invention a halogenated (e.g. iodinated) resin may be used as a deactivation chemical reagent against toxic chemical agents, namely toxic chemical agents such as nerve agents, e.g., VX and the G series of nerve agents.
In accordance with one further aspect of the present invention, phosphonothiolates and phosphonothioic acids (e.g. see above formula (I) with respect thereto) may be detoxified using a halogenated resin. In accordance with the present invention, a means (e.g. method, system, etc..) is thus in particular provided for detoxifying substituted and unsubstituted phosphonothiolates and phosphonothioic acids (e.g. VX). As mentioned above, the phosphonothiolate or phosphonothioic acid is contacted with a sufficient amount of a halogenated resin (e.g. demand halogenated resin), for a sufficient time and under conditions sufficient to produce a reaction product having less toxicity than the phosphonothiolate or phosphonothioic acid.
The chemical warfare agent to be treated in accordance with the present invention may for example be from the group consisting of bis-(2-chloroethyl) sulfide (HD), pinacolyl methylphosphonofluoridate (GD), and O-ethyl S-(2-diisopropylamino)ethyl methylphosphonothiolate, (VX).
Deactivation contact is of course to be for a sufficient time and under conditions (i.e. residence or contact time, concentration ratios, temperature, pressure and the like) which are sufficient to produce a reaction product having less toxicity than the toxic chemical agent.
The deactivation contact for the method(s) system etc, of the present invention may as mentioned above take place within confining means; the confining means may, for example, be a sealable container in which the reactants may be placed for reaction and unsealed to remove the reaction product(s) (e.g. reactor with a sealable cover). Alternatively, the confining means may take the form of a chromatographic like column packed with halogenated resin, the column defining a fluid path means for the movement of fluid therethrough etc..
Deactivation of toxic chemical agents may be accomplished by mixing the toxic chemical with a deactivating amount of the described resin, e.g. such simple contact may occur in a sealed container.
The deactivation contact may, as mentioned above, take place in a chromatographic like column by packed with halide-resin. The column may be sized so as to have any desired or necessary length to width ratio; the length to width ratio may for example be 20:1. The halide-resin packed into the column may be comprised of particles of the sizes discussed herein; the halide-resin may in particular comprise a 20 micron powder, i.e. at least a substantial amount of the halide resin is about 20 microns in size. The column may have fluid input and fluid output means for the delivery to and removal therefrom of a fluid phase material. The flow rate of toxic chemical agent (in a fluid phase) through the column may be selected so as to provide the desire residence time; e.g. flowthrough may be such as to provide a 10 minute exposure of the toxic chemical agent to the halide-resin, The column if so desired or necessary may be provided with a transparent wall about one third the way down from the top of the column; this transparent portion may be used for visual verification of the continuing activity of the resin, i.e. as the iodine is expended the colour of the resin will change so as to give some forewarning that resin is losing its potency and needs to be replaced.
As mentioned above the contact between the halide-resin and the toxic chemical agent is to be for a sufficient time and under conditions which are sufficient to produce a reaction product having less toxicity than said toxic chemical agent. For purposes of the present invention, it will be understood by those of ordinary skill in the art that the term xe2x80x9csufficientxe2x80x9d as used it conjunction with the terms xe2x80x9camountxe2x80x9d, xe2x80x9ctimexe2x80x9d and xe2x80x9cconditionsxe2x80x9d represents a quantitative value which represents that amount which provides a satisfactory and desired result, i.e. detoxifying toxic chemical agents. The amounts, conditions and time required to achieve the desired result will, of course, vary somewhat based upon the type and amount of toxic chemical agent present, Temperature may be dependent on the chemical to be deactivated; temperature may be selected so as to reduce the partial vapour pressure of the chemical to a minimum level while maintaining a viscosity capable of allowing mixing of the toxic chemical agent and the halide-resin. The contact may for example occur at 22 degrees C. for VX and detoxification may occur in less than 1 hour. Commonly, the halide resin will be used in volumetric excess relative to the toxic chemical agent, e.g. for treating VX the volumetric ratio may be 3 parts (e.g. by volume) halide resin (e.g. a halide-resin comprising 50% by weight iodine) to 2 parts VX (e.g. by volume). In order to insure total detoxification, it may be necessary to utilize a relatively large excess of the decontaminating chemical compound i.e, halide-resin vis-a-vis the toxic chemical agent.
In accordance with the present invention, a halogen substance capable of deactivating toxic chemical agents may comprise halide-resin (i.e. halogenated-resin) particles; the particle or granular from is advantageous due to the high surface area provided for contact with the toxic chemical agent (see U.S. Pat. No. 5,639,452). The halide-resin particles may, for example, be selected or segregated so as to obtain an amount (i.e. group) of particle wherein all or at least a substantial proportion (or amount) of said segregated particles have a particle size greater than 300 microns; the segregated halide-resin may, for example, comprise granules or particles having a size in the range of from 0.2 mm to 0.8 cm (e.g. of from 0.35 mm to 56 mm). On the other hand, in accordance with a particular aspect of the present invention all or at least a substantial proportion (or amount) of the segregated halide-resin particles may have a particle size in the range of about 0.1-300 microns; the halide-resin particles may, for example, have a particle size substantially in the range of about 0.1-3 microns, 3-5 microns, 3-15 microns, or 5-15 microns. Depending on the requirements the halide-resin may, if so desired, comprise a mixture of particles having a large or wide range of particle sizes; e.g. the halide resin may comprise 1 part by weight beads (e.g. 0.2 to 0.5 mm), 2 parts by weight fragments (e.g. 150 to 300 microns) and 1 part by weight dust sized particles (e.g. 0.1 to 3 microns). As used herein the expression xe2x80x9ca substantial proportionxe2x80x9d in relation to particle size is to be understood as characterizing the particles as comprising at least a majority (i.e. more than 50%) by weight of the particles.
In accordance with the present invention a halogen substance capable of deactivating toxic chemical agents may comprise halide-resin particles comprising polyhalide ions having a valence of xe2x88x921 absorbed or impregnated into resin particles; the particles may have a size as mentioned above, e.g. the particles may have a particle size substantially in the range of about 0. 1-300 microns.
The halide-resin may be characterized in that it may be obtained from a process wherein an activated halogenated resin (i.e. an initially halogenated resin) may be ground and segregated into particles of desired size, e.g. particles substantially in the range of about 0.1-300 microns. Thereafter the particles of desired size may be exposed to a sufficient amount of a halogen-material absorbable by the activated resin to form converted resin particles having a greater proportion of available ionic halogen (relative to the initial ground activated halogen-resin), with the halogen-material being selected from the group consisting of I2, Cl2, Br2, F as well as polyiodide ions having, a valence of xe2x88x921.
As used herein, the terms xe2x80x9cpolyhalide,xe2x80x9d xe2x80x9cpolyhalide ions,xe2x80x9d and the like refer to or characterize a material or a complex that has three or more halogen atoms and a valence of xe2x88x921, and which may be formed if a molecular halogen (e.g., bromine as Br) combines with a monovalent trihalide ion (e.g. a triiodide ion) or pentahalide ion (pentaiodide ion). Iodine and chlorine also may be used as a source of molecular halogen, Similarly, the terms xe2x80x9cpolylodide,xe2x80x9d xe2x80x9cpolyiodide ions,xe2x80x9d and the like refer to or characterize a material or a complex that has three or more Iodine atoms and that may be formed if molecular iodine combines with the monovalent triiodide ion. The terms xe2x80x9ctriiodide, xe2x80x9ctriiodide ion,xe2x80x9d and the like refer to or characterize a material or a complex that contains three iodine atoms and has a valence of xe2x88x921. The triiodide ion herein therefore is a complex ion which may be considered as comprising molecular iodine (i.e., iodine as I2) and an Iodine ion (Ixe2x80x94).
The invention includes a method of making a resin substance or composition, comprising the steps of
providing an activated halide-resin (e.g. obtained by subjecting starting resin to the high temperature/pressure process described in U.S. Pat. No. 5,639,452 (herein sometimes referred to as the xe2x80x9cMessier Processxe2x80x9d));
forming the activated resin into particles;
selecting or segregating obtained halogen-resin particles substantially in the range of about 0.1-300 microns; and
forming converted resin particles from the segregated particles of about 0.1-300 microns having a greater proportion of available ionic halogen relative to the initial segregated particles.
The activated resin may be used per se as a halide-resin for contact with a toxic chemical agent or as a starting material for an above mentioned converted halide-resin. The activated resin for making the converted halide resin may be an anionic triiodide resin, a divinyl styrene triiodide resin, etc.
The starting resin for the preparation of the activated resin may be any suitable (known) resin which may give rise to a halogenated resin able to deactivate a toxic chemical agent.
The starting resin for the preparation of the activated resin may be any (known) anion exchange resin (for example, with those such as are described in more detail in the above-mentioned United States patents such as U.S. Pat. Nos. 3,923,665 and 5,639,452). The starting resin may for example be a strong base anion exchange resin. A quaternary ammonium anion exchange resin is, however, preferred. As used herein, it is to be understood that the expression xe2x80x9cstrong base anion exchange resinxe2x80x9d designates a class of resins which either contain strongly basic xe2x80x9ccationicxe2x80x9d groups, such as quaternary ammonium groups or which have strongly basic properties which are substantially equivalent to quaternary ammonium exchange resins. U.S. Pat. Nos. 3,923,665 and 3,817,860 identify a number of commercially available quaternary ammonium resins, as well as other strong base resins including tertiary sulfonium resins, quaternary phosphonium resins, alkyl pyridinium resins and the like. The starting resin may be a strong base anion exchange resin having strongly basic groups in a salt form; the resin may be in any salt form provided that the anion is exchangeable with the iodine member (e.g. with triiodide ion). The starting resins which may be used herein may, for example, be in a hydroxyl form, a chloride form, an iodide form or in another salt (e.g. sulphate) form provided as mentioned above, that the anion is exchangeable with the iodine member (e.g. with triiodide ion). In accordance with the present invention the anion exchange resin may, for example, be a quaternary ammonium anion exchange resin; in his case the anion exchange resin may be in the iodide form Ixe2x88x92, in the chloride form Clxe2x88x92; in the hydroxyl form OHxe2x88x92; etc..
Commercially available quaternary ammonium anion exchange resins which can be used in accordance with the present invention include in particular, Amberlite IRA-401 S, Amberlite IR-400 (Clxe2x88x92), Amberlite IR-400 (OHxe2x88x92), etc., (from Rohm and Hass) which may be obtained in granular form. These resins may for example, contain quaternary ammonium exchange groups which are bonded to styrene-divinyl benzene polymer chains.
Converted resin particles may be formed by again following the process as described in U.S. Pat. No. 5,639,452 i.e. after particle segregation the halide-resin particles of desired size (i.e. of size less the 300 microns) may be subjected to the xe2x80x9cMessier Processxe2x80x9d. Thus converted resin particles may be formed by exposing the segregated halogen-resin particles to a sufficient amount of a halogen-material to form converted resin particles. The halogen-material may, for example, be selected from the group consisting of Cl2, I2, Br2, polyhalide ions having a valence of xe2x88x921 and mixtures thereof. Absorption of at least a portion of the halogen-material may be effected at elevated temperatures, i.e., temperatures higher than 100xc2x0 C. and up to 210xc2x0 C., and elevated pressures, i.e., pressures greater than atmospheric pressure and up to 100 psi. (for suitable process conditions please see U.S. Pat. No. 5,639,452 mentioned above).
The reaction product(s) obtainable by treating VX with a halide-resin as described herein shows significantly reduced toxic effects for the major reaction products identified, Although the exact chemical route leading to the deactivation of VX is not fully understood, the reaction does not appear to lead to a dynamic equilibrium and the reforming of VX. It may be interrupted by introducing a stop reaction agent such as for example sodium thiosulphate, ascorbic acid and the like. Thus the reaction may be stopped by such stop reaction agent, once a desired product ratio has been achieved relative to the initial amount of toxic chemical agent; the reaction products (or a separated fraction thereof) may as desired or necessary be recontacted with halide resin as desired or necessary. The desired stopping point may vary depending on the desired outcome, for example on whether a least toxic material may be obtained, whether the obtained product (s) may be a useful by-product(s), whether the obtained product (s) may be safely incinerated. This exemplified procedure may be applicable to other phosphonothiolates and phosphonothioic acids and including substituted phosphonothiolates and phosphonothioic acids the treatment conditions of which may be easily determined by those skilled in the art.
If desired, to tailor the reaction products to eliminate potentially toxic products, a toxic chemical agent (e.g. VX) may possibly be contacted with a deactivating amount of a halogenated resin either in the presence of liquid I2 or after an initial contact between the toxic chemical agent and liquid I2. A contact between liquid I2 and VX for example may lead to the formation of EA2192 which when contacted with halide-resin as described herein may lead to a mixture without VX or EA2192. This pretreatment may be used to remove R1 or R3 (e.g. ethyl) group to prevent formation of a minor reaction product and EVX which is a substitution product derived by removing the R1 or R3 and insert or attaching it to the R2 group.